The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological progress in IC manufacture has produced several generations of ICs, and each generation fabricates smaller and more complex circuits than the previous generation. Various types of semiconductor devices performing different functions are integrated and packaged into a single assembly or package. As the demand for miniaturization, higher speed and lower power consumption, there has grown a need for smaller packaging techniques of semiconductor dies. However, as features such as vertical plugs scaling down continues, conventional packaging techniques have not been entirely satisfactory in all respects.